Pass on the side it's named after
A cardinal mark sits in one of the four quadrants around a danger, and its name tells you where the safe water is. Pass north of a north cardinal, east of an east cardinal, and so on. They're used to mark the deepest water, the safe side of a hazard such as a rock or wreck, or a feature in a channel like a bend or junction.
- North
- East
- South
- West
Topmarks: two black cones
- North: both point up, towards north.
- South: both point down, towards south.
- East: points apart, base to base. It looks like an egg, and E is for egg.
- West: points together, tip to tip. It looks like a wine glass, and W is for wine glass (or a woman's waist).
Colours: the cones point to the black
Once you know the topmark, you know the colours, because the cones point to where the black is on the body.
- North cones point up, so black is at the top: black over yellow.
- South cones point down, so black is at the bottom: yellow over black.
- East cones point to the top and bottom, so it's black with a yellow band.
- West cones point to the middle, so it's yellow with a black band.
Lights: read them like a clock
All cardinal marks show white quick (Q, 50 to 60 flashes a minute) or very quick (VQ, 100 to 120 a minute) flashing lights. Picture a clock face: east is at 3, south at 6, west at 9, so they flash in groups of three, six and nine. North, at 12, flashes continuously.
| Mark | Topmark | Colours | Light |
|---|---|---|---|
| North | Both cones point up | Black over yellow | VQ or Q (continuous) |
| East | Points apart (base to base) | Black, yellow band, black | VQ(3) 5s or Q(3) 10s |
| South | Both cones point down | Yellow over black | VQ(6)+LFl 10s or Q(6)+LFl 15s |
| West | Points together (tip to tip) | Yellow, black band, yellow | VQ(9) 10s or Q(9) 15s |
South adds a long flash after its six so that, in a swell or poor visibility, it can't be mistaken for the three of an east or the nine of a west.
The marks you'll be asked about next
- Isolated danger: black with red bands, two black balls, white Fl(2). A small danger with navigable water all round.
- Safe water: red and white vertical stripes, one red ball, white isophase, occulting, long flash every 10 seconds or Morse A. A landfall or the start of a channel.
- Special mark: yellow, with a yellow X topmark and a yellow light. Marks something like a spoil ground, a cable or a racing mark, not a navigational danger.
- Emergency wreck marking buoy: blue and yellow vertical stripes, a yellow upright cross, and an alternating blue and yellow flashing light. Marks a new wreck not yet on the chart.